The CAD Nonextraction Philosophy: What Are the Differences Between Coordinated Arch Development® By Raphael Greenfield, DDS, MScD An excerpt from Dr. Greenfield's new textbook, “NON EX FACTORS, 98.5% Nonextraction Therapy Using Coordinated Arch Development.” This article is the property of the AOS and Dr. Raphael Greenfield. No copies of this article may be reproduced or distributed without permission of the AOS. F or more than a century, the controversy of treating tooth-size and arch length discrepancies, either with or without extraction of permanent teeth has been at the forefront of diagnosis and treatment planning. Hunter’s proposal 200 years ago to extract maxillary first bicuspids to reduce maxillary procumben- cies led to capricious extraction of teeth to resolve crowd- ing and procumbencies for the next 100 years. Disregard of the functional and esthetic consequences of extraction treatment encouraged the Angle school to take the oppo- site position at the turn of the century. Angle’s strong personality and unrelenting nonex- traction stance overcame Case’s camp advocating maxillary first premolar extraction philosophy for the treatment of most malocclusions (actually only 4% of cases). For the next 25 years, treatment was heavily weighed towards the nonextraction approach with indiscriminate expansion of the arches. Intercanine and intermolar widths were increased well beyond the “neutral zone” and the mandibular incisors were flared labially to resolve crowding. Basal bone discrepancies were corrected primarily by mandibular dental advancement and/or repositioning of the post-pubertal mandible into an unstable anterior posture. Angle also chose a heavy intra-oral force (Class II elastics) as the only relevant mechanotherapy to influence favorable growth, while denying the efficacy of extra oral force. Treatment was initiated after the 18 May/June 2010 JAOS eruption of second molars, which usually negated the period of significant craniofacial growth that would have reduced the complexity of the discrepancy. The flaring of the anterior teeth to camouflage skeletal discrepancies resulted in many bimaxillary protrusions. This compromise of facial esthetics did not sit well with many in the orthodontic community. Over time, Case’s position would be justified as expanded arches relapsed in great frequency, resulting in disaffection with nonextraction treatment. The pendulum then swung towards extraction treatment for the next 30 years as a routine approach to orthodontic care, (80% of cases). The orthodontic community led by Tweed, used cephalometrics to support their position. The teeth most frequently selected for extraction were the mandibular and maxil- lary first premolars. Tweed’s strong and forceful personality allowed him, with minimal resistance, to establish “normal” cephalo- metric values for an ideal occlusion. He illustrated facial types that contained these values, which he considered to be esthetic to support his position. The mandibular incisor position was the cornerstone of his analysis and was used effectively to discredit the nonextraction approach. He advocated “uprighting” the lower incisors to enhance stability and esthetics and thus succeed where expansionists failed. Tweed’s approach strongly influenced orthodontic treat- ment decisions well into the late 1960s and early 1970s, (CAD) Versus Expansion?
Journal of the American Orthodontic Society May-June 2010: Page 18
